Cytochemical demonstration of adenylate and guanylate cyclases in vascular smooth muscle of circle of Willis

Mesenchymal stem cells improved the ultrastructural morphology of cerebral tissues after subarachnoid hemorrhage in rats

Subarachnoid hemorrhage (SAH) causes widespread disruption in the cerebral architecture.The process of SAH is complicated and many people lose their lives or become disabled after injury. Mesenchymal stem cells (MSCs) are considered as good candidate for repair of cerebral damage. The aim was to assess the ultrastructural changes in the rat cerebral tissue after intravenous transplantation of MSCs. Female Wistar rats (8 per group) weighing 275~300 g were assigned to control (SAH+PBS) and experimental groups (SAH+MSCs).The samples from middle cerebral arterial wall and parietal cerebral tissue were prepared for transmission electron microscopy (TEM) according to standard protocol. Fine architectures of the vessel wall, including the contraction of the inner layer, smooth muscle layer,as well as neural cells were observed after SAH. Cerebral arterial wall and cortex, including neuronal and glial cells were injured post SAH. But, administration of MSCs improved the structural integrity of cerebral tissues. Changes were much more balanced with their relative improvement in some areas. The role of MSCs for repairing the injured cerebral tissues post experimental SAH was approved by electron microscopy.

Cerebral vasospasm

Cerebral vasospasm is an important component of pathological entities such as migraine, subarachnoid hemorrhage (SAH), head trauma, post cerebral ischemia and/or hypoxia. The mechanisms underlying cerebral vasospasm in these diseases are not completely understood. Neurochemical and morphological factors involved in the cerebral circulation control are reviewed in this article. The circulatory changes observed after subarachnoid hemorrhage are taken as a model. It is concluded that multiple biochemical, physiological and morphological factors are involved in the cerebral vascular responses after SAH. Possible treatment alternatives for cerebral vasospasm based on its etiology are discussed.

Effect of prostacyclin and adenosine triphosphate on vasospasm of canine basilar artery

Cerebral vasospasm is one of the most important factors influencing morbidity and mortality of intracranial operations or diseases. Platelet aggregation and adhesion is increased in spastic vessels. Degradation of platelets liberates mediators, which in turn increase vasospasm, thus creating a vicious cycle. Healthy vessels cope with this by increasing the synthesis of prostacyclin. The purpose of this study was to increase experimentally the levels of arterial prostacyclin and adenosine triphosphate (ATP) in animals through intraarterial injection of these substances because they are lower in spastic vessels. Prostacyclin promotes antiaggregation and dilatation, increases blood flow, inhibits thromboxane A2, and prevents synthesis of angiotensin II. Most of these effects were done by increasing cyclic adenosine monophosphate (cAMP). After injecting autogenous blood into the cisterna magna of male dogs, both the acute and chronic phases of vasospasm and the degenerative changes in the arterial wall were observed. Injecting ATP increased the severity of vasospasm. During vasospasm it was found that when prostacyclin is used intraarterially, vasodilatation began, but degeneration of the arterial wall could not be prevented. In the group of animals in which both ATP and prostacyclin were used, there was no degeneration of the arterial wall and the basilar artery was seen to be normal when viewed under the electron microscope.